In Minecraft, I play competitive PVP. I have changed my sprint hotkey to R and press W and R to sprint. I then release R and sprint that way. However, it seems that sometimes when I get comboed, R and W do absolutely nothing and i am walking away from my opponent, leaving me helpless. How do I sprint correctly?
There's a few factors that can go into this, depending on your situation.
If you play online, lag and packet loss can be a factor. Sometimes commands don't get sent properly, causing your character to not do what you want them to do (like sprinting). In this case, there's not much that can be done outside of making sure that other people in the house aren't using the internet for big downloads and uploads at the same time, or upgrading your internet plan.
Lag can still affect you if you play locally as well, so you'll need to make sure that you have enough RAM to run Minecraft properly, or close other programs that are using RAM.
The only other thing is obviously to keep an eye on your hunger bar. If it drops below 6 (3 full bars) you will not be able to sprint.